This happened during a cultural festival at Umesato School. Haruyuki and the girls he invited, under the watchful eye of Kuroyukihime, enjoyed the magnificent fireworks display. The festival, into which so much work had been invested, was very bright. But in the midst of the festival, Rin, who Magenta Sizza had infected with the ISS kit the day before, fainted. In an emergency, Kuroyukihime and the others decide to go to battle with Archangel Metatron, who is protecting the body of the ISS kit. In order to prepare as much as possible for the battle, they first go to save Aqua Current. But the furious attacks of Seiryuu, the defender of the East Gate of the Imperial Castle, greatly injure their group. And then Haruyuki is forced to face the horror of the strongest and most dangerous of all Seiryuu's attacks, "Level Draw"!..